<popup#table-cells>
  <div>
    <toolbar.cols>
      <button.insert-col-before tooltip="insert column before"/>
      <button.insert-col-after  tooltip="insert column after" />
      <button.delete-col tooltip="delete column(s)" />
    </toolbar>
    <toolbar.rows>
      <button.insert-row-before tooltip="insert row before" />
      <button.insert-row-after tooltip="insert row after"/>
      <button.delete-row tooltip="delete row(s)"/>
    </toolbar>
    <toolbar.cell>
      <button.merge-cells tooltip="merge cells" />
      <button.split-cells tooltip="split cell(s)" />
    </toolbar>
  </div>
</popup>